Tractor



H. F. SCHMIDT.

TEACGB.

APrucmou man 1m29, ma.

Patented Oct. 26, 1920.

H. F. SCHMIDT.

TRACTOR.

-SHEET 4.

Fatemi oef. 26,1920.

4 SHETS HUGO F. SCHMIDT, 0F HICAGO, ILLINOIS.

TRAUTOR.

Application led January 29, 1918.

To all whom it may concern.'

Be it known that I, HUoo F. SCHMIDT, a citizen of the United States, residing in Chica o, Cook county, Illinois, have invente new and useful Improvements in Tractors, of which the following is a specification.

This invention relates to improvements in tractors, and more especially to a linked track or caterpillar drive chain included in the mechanism of a tractor. In the general type of caterpillar drive chains embodied in a tractor machine of ordinary form there is a pair of endless linked tracks or linked belts, each of which is directed about two wheels spaced apart to provide a relatively Hat or horizontal section of the track carrying the wei ht of the machine on the ground; and 1n order to stiffen this section of the track and prevent it from bending up between the two wheels, the common expedient is to support the weight of the machine on this part of the chain through a series of rollers or wheels. This necessarily produces a heavy and clums mechanism, requiring linked tracks or c ains of considerable length and width to properly dis` tribute the weight of the mechanism when the machine is traveling on soft ground, and as the strengthening and stifening of the machine must in general be in proportion to its length, the result is usuallythat the tractor machine becomes a huge and ponderous affair, which is expensive to build and operate and diilicult to keep in order and repair. In order to overcome some of these defects and disadvantages, I have shown in my (zo-pending ap lication No. 147098, filed February 7, 191 a form of linked track or drive chain designed to include inherent means for stii'ening or trussing the lower section of track len h which travels on the ground, so as to orm an inverted arch carrying the wei ht of the machine through a pair of wheeIs around which the chain or track is directed. One of the objects of this invention is to rovide further lmprovements in the genera type of drive chain, or linked track shown in the said ap- Specicaton of Letters Patent.

Patented Oct. 26, 1920. Serial No. 214,413.

plication, a linked track or chain embodying the present improvements, bein shown 1n the accompanying drawings, in w ich:

Flgure 1 is a view of the complete drive cham in side elevation, with some of the link s shown in radial section.

Fig. 2 is a view showing the complete chain in top plan.

Fig. 3 is a top plan view of a few links in the lower part of the chain.

Fig. 4 is a transverse vertical section on the line 4 4 of Fig. 1.

Fig. 5 is a view in perspective showing one of the rail pieces which is used in combination with the chain links to stiifen the latter and carry the load.

Fig. 6 is a radial section through the rail piece shown in Fig. 5.

Fig. 7 is a view partly in side elevation and partly in radial section showing a modified form of the chain.

Fig. 8 is a view showin .fra entary portions of two rail pieces o mo ied form.

Fig. 9 is a view in side elevation showing a complete drive chain of a further modified form.

Fig. 10 is a top plan view showing some of the links in the chain shown in Fig. 9.

Fig. 11 is a pers ctive view of one of the links shown in 4ig. lO.

As shown in said drawings in Figs. 1 to 6 inclusive, the complete tractor machine is made with a unitary frame structure comprising an engine 1 and a transmission gearset housing 2, which are bolted together and supported on each side through a sprocket wheel 3 and an idler wheel 4 in an endless linked track or belt' 8 which is directed about them.. The sprocket wheel 3 is driven through suitable mechanism in the transmission gear housing 2 and the weight of the machine is carried on the wheel 4 by a beam or bar 10, one end of which is pivotally connected to the housing 2 and the other end of which is shackled to a spring (not shown) supporting the forward end of the engine frame 1.

The continuous or endless linked track or chain 8 is formed of a number of links 15,

all of them alike, which are articulated toether by means of pivot ins 16. Each Fink 15, which may refera ly be made of a plate of uniform t ickness, cut and bent to the desired shape, comprises an integral flat tread part 20 (see Fi 4) with a pair of vertical side walls 21. he side walls are trapezoidal in form, being wider at their inner edges (or those ed s which are adjacent to the wheels 3 an 4) than at their outer edges. The two walls are also narrowed to ether at one end of each link so that the atter may telescope into the s ace between the two walls of the next succee ing link, thus permitting all the links to be hinged or ivoted together by the bolts or ins 16; w ich latter are secured in place y s lit pins 25.

ithin the box-like structure formed by the tread plate 2O and the two side walls 21 of each link, is placed one of the rail lpieces shown in Fi 5, each of these being s aped somewhat lie the letter T and comprisin a radially extending, center part 30 wit integral, tangential y projecting feet (31 and 32). The two feet (31 and 32) overlap at their adjacent ends and are staggered or offset in relation to each other so as to leave a cleft 33 between them, and so that each foot may overlap the foot which extends toward it from the next adjacent link. The block or piece 30 is pivotall mounted on the pin 16, which latter exten s through openm in the overlapping parts of the two feet 31 and 32, an the sprocket teeth, 34, enter the cleft 33 and drive the link through the pin 16. Each foot 31 and 32 also terminates in a toe 41 and 42 respectively `and at the center of each block is a led e or heel 45 adapted for engagement b t e toe 41 at the end of the foot 31 whic extends toward it from the next adjacent link. The blocks thus form a series of stops limiting the turning movement of each pair of links about its pivot pin 16, so that while the articulated series of chain links and blocks are free to bend about the two wheels 3 and 4, with each link traveling in an elliptical path, a reverse bending of any pair of links is prevented by the ends of their two overlapping feet 31 and 32, coming into engagement with the respective heels or ledges 45, and the bottom section of chain links forms an inverted arch to carry the wei ht of the two wheels 3 and 4 on the groun In order to reduce wear on the pins 16, each of these is surrounded by a tubular sleeve or bushin 50 to receive the thrust of the sprocket teet One end of each sleeve or bushing, which projects beyond the wall of the corresponding block or rail piece 30, is slotted, as indicated at 52, and enga es in a correspondingly shaped opening in t e wall of the inner link 15, while the pivot. pin 16 is fiattened at one end to enga e 1n a correspondingly shaped opening 1n t e wall of the outer link 15; so that all turning movement between the sleeve and the inner link, and between the pin and the outer link, respectively, is prevented, and the rubbing friction is taken oli' of the openin s in the link walls and distributed over t e pin and the bushing. The outer and inner pairs of walls 21 are spaced apart by thrust washers 55 and the inner walls are separated from the inclosed thrust block 30 by a pair of washers 56.

1n order to provide eiiective lubrication of the pivot joint between each pair of links, the large center or head part of the inclosed block 3() is made hollow, as cated in Figs. 4 and 6, roviding a lar e oil chamber 60 which is lled through llin openings 61. From this oil chamber the oi escapes through restricted openings 64, and corresponding openings through the bushing 50, to lubricate the pivot pin 16. As the openings 64 are restricted 1n size, the oil cannot escape freely from the oil chamber even when the openings 64 and 65 correspond and the chamber is inverted, as the oil is confined by atmospheric ressure and can escape only by capillarity, t ius pro viding effective lubrication without any Waste of oil. The center or head part of each rail piece 30 is also made with a lip or projection 70, reinforced by a rib 71, to close the opening between each pair of links in the lower forward part of the chain when the machine is moving ahead, as indicated at 72, and prevent dirt and stones from cloggin the mechanism. The links may also be tted with cleats or flanges 75 to afford better traction, the latter being shown considerably wider than the links to provide lateral stability. When the machine is operating in limited space, these can be removed.

It will thus be seen that the overlapping rail pieces 30, articulated together 1n an endless series directed about the two wheels 3 and 4 on each side, form a foldin track or rail, with a smooth, uninterru te trackway or rail-tread, 76 (Fig. 1 for the wheels to run on; the side walls 21 of each link being recessed, as indicated at 77 Fig. 1), to clear the rims of the wheels. ince the track-way 76 projects beyond the ver' tical radii of the respective wheels, in each direction, the wheels will roll along this track-way without jolt or jar, and provide a smooth and efficient operation of the mechanism.

In Fig. 7 is illustrated a form of the drive chain in which the links 15 are replaced by flat plates 90 similar to the link plates of indian ordinary block chain of common form and without any tread part, in th1s case the rail pieces 91 traveling directly upon the ground. These latter parts are similar in all respects to the rail pieces 30 except that in lace of the tangential extension 70, each rail) piece or block is made with two extensions or projections 92 in opposite directions so that when` the lower art of the chain is at u on the ground t ese projections will near y meet and form a substantially continuous track to carry the weight of the machine, while their upper ed es form a smooth, unbroken track-way 93 or the two wheels to run on.

In Fig. 8 are illustrated fragmentary parts of a pair of rail pieces corresponding to the arts 30 but somewhat modified in form, t e extension 79 from one. of the pieces having a toe 80 which engages upon a heel 81 upon the other piece in such manner that the thrust comes at right angles to the tangential line through the pivot 1n, as indicated by the two crossed `lines. he eect of this is to prevent any bending force being imparted through the thrust between the toe and the heel of the engaging parts. As a further and separate improvement, there mav also be interposed a resilient ad 82 of ru'bber, leather, or relatively so er metal between the two arts.

In Figs. 9 and 10 is illustrated a further modified form of my improved drive chain, in which each link is a box-like structure comprising two vertical, parallel side walls 100` 101 and an integral connecting tread part 102 adapted to rest on the ground in the lower part of the chain travel, as shown in Fig. 9. For the purpose of articulatin the links together, each side wall 100 and 101 is made integral with a pair of hubs, 105, at one end of the link and a similar pair of hubs, 106, at the opposite end of the link; the first pair being spaced apart such distance as to embrace the second pairibetween them, whereby the links may be strung together in an endless series with each pair connected by a pivot in or bolt 110. The pivot pins 110 are attened or squared at one end and engaged in correspondingly shaped openings in the hubs 105 to prevent the pins from rotating, and they are secured in place by split pins 115 at each end; while between the pivot bolts and ythe openings in the hubs 106 are interposed bushings 116 which-are fixed in place by pins or set screws 118 to prevent them from rotating in their hubs, so that all of the rubbing friction in the bending of each pair of links is confined to the surface between the pins and their bushings. To provide for lubrication of these joints each link is made integral with a large oil chamber 120 adapted for filling throu h a sealed opening 121, with a restricted oi outlet opening to the bushing and thence through the latter fto the pivot bolt; the arrangement being similar to that above described for lubrication of the links shown in Figs. 1 to .6. In the straightening out of the chain 1n the lower and upper parts of its travel the oil chambers 120 telescope between the walls 10() and 101 of the next succeeding nlinks, but the oil-filling openings 120 remaln accessible through curved recesses 125 in the ed es of these walls.

' he chain is directed around a sprocket wheel 130 and an idler wheel 131, and in order to bridge the gap between the wheels and prevent the lower section of chain from bending up between the wheels there is formed on the closed end of each link a ledge or abutment 135 adapted for engagement against a corresponding part, 136, on the end of the next succeeding link to limit the relative pivotal movement of each pair of links and prevent them from bendin in a reverse angle up between the two wligeels 130 and 131.

Each link is also made integral with a pair of brackets 140, which extend tan entially from the radially inner edge o its walls 100 and 101 in one direction, and with a similar pair of brackets 141 at its other end extending in the opposite direction; the first pair being so spaced apart as to be embraced between the walls 100 and 101 of the next succeeding link, while the air of brackets 141 overlap the walls of tige next succeeding link in the opposite direction. The effect of these brackets, in their overlapping relation to the side walls of the links and to each other, is to form a straight unbroken track indicated by the line 150 in Fig. 9, for the two wheels to roll upon; the edge of each wall 100 and 101 between the two pairs of brackets being cut away on a curved line, indicated at 152', so that the Wheels rest directly upon these brackets and each link will sup ort its load as soon as it reaches the groung under the front wheel, and will carry it until it starts to leave the ground over the rear wheel. Thus, assumlng a forward movement of the machine in the direction indicated by the u per arrow, the link A lies flat on the groun to support the weight of the wheel 131and will con- Y upward travel, thus preventing the jerking of the chain which would result from the sudden shftin of the load from one link to another at t e rear end of the chain.

When the chains travel about the two wheels the brackets or shelves 140 and 141 project tangentially from their rims and the curved recesses 152 permit the hubs 105 and 106 to engage directl upon the rims of the wheels and the sproc et teeth to mesh with the bushings for driving the chain, while the straightening out of the chain in the lower part f its travel brings all of the brackets or shelves 140 and 141 into line to form the straight unbroken track-Way 150.

I claim as my invention:

1. A drive chain for tractors comprisin an endless series of hollow links, fastened together by pivots, the pivots also carrying rail pieces, or blocks, within the links.

2. A drive chain for tractors comprisin an endless series of hollow links fastene together by pivots, the pivots also carrying rail pieces, or blocks,within the links, each of said rail pieces having a heel, and a toe adapted to engage against the heel of the next succeedn rail piece.

3. A drive c ain for tractors comprisin an endless series of hollow links fastened together by pivots, the pivots also carryi ra1l pieces, or blocks, wlthin the linksz sai rail pieces overlapping to form an uninterrupted track-way for a load supporting wheel.

4. A drive chain for tractors comprisin an endless series of hollow links fastene together by pivots, the pivots also carrying ra1l pieces, or blocks, wlthin thelinks, each of said rail pieces havin therein an oil chamber with a restricte outlet opening to the pivot.

In wltness'whereof, I have hereunto subscribed my name this twenty-fourth day of January, 1918.

HUGO F. SCHMIDT. 

